Method of forming interlayer insulation film

ABSTRACT

A method of forming an interlayer insulation film on a semiconductor substrate using plasma CVD includes introducing a source gas into a reaction chamber, applying radio-frequency power after the source gas is brought in, introducing an oxidizing gas with or without an additive gas into the reaction chamber after the completion of supplying the source gas and applying the radio-frequency power, and applying the radio-frequency power again. The concentration of the oxidizing gas may be 0.3% or higher and a processing time period by the oxidizing gas may be three seconds or longer.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a method of forming an interlayerinsulation film used for multilayer interconnects and particularlyrelates to a method of forming an interlayer insulation film having alow dielectric constant, high mechanical strength, and lowwater-repellency.

2. Description of the Related Art

In semiconductor integrated circuits, miniaturization has been pursuedin response to demands on increased chip speed and performance. In thepast, aluminum had been used as a material for multilayer interconnects.As interconnects had become minute and long, current densities hadincreased relatively, causing electromigration during use. Becausealuminum has comparatively high electric resistivity, a problem withsignal delay also occurred.

Consequently, copper having high resistance to disconnections andcomparatively small electric resistivity was brought to attention inplace of aluminum. In 1997, Cu trench filling interconnect technologycalled “Dual-Damascene” was developed by IBM and Motorola. Differentfrom conventional methods in which an interlayer is filled with aninsulation film after an interconnect is formed by processing an AI filmconvexly by etching, in this technology, an interconnect is formed by:An interlayer insulation film is trench-etched, a Cu thin film iselectroplated/deposited on the entire surface, the copper is polished bythe Chemical Mechanical Polishing (CMP) process so that the copperremains only in a trench portion.

In the Damascene interconnect technology, application of a low-kinsulation film is essential for solving signal delay problems. As low-kinsulation films, there are, for example, an inorganic SOG (siliconoxide glass) film deposited by a spin coat process, a fluorinatedamorphous carbon film deposited by plasma CVD using CxFyHz as a sourcegas, or a SixCyOx film deposited by plasma CVD using silicon hydrocarbonas a source gas and others. Of these low-k films, the SixCyOx film ismost preferable as it possesses both a low dielectric constant andmechanical strength.

SUMMARY OF THE INVENTION

The SixCyOx film, however, has a property that its surface exhibitshydrophobicity because it contains many —CHx bonds. Because a liquidcontaining OH groups is used as a polishing fluid (slurry) in a CMPprocess, which is a post-process of a process of forming an insulationfilm, the polishing fluid does not blend in with a surface sufficientlyif the surface of an insulation film has high water-repellency and lowhydrophobicity. As a result, a problem in uneven polishing is caused.

If a device for the post-process is provided separately so as to lowerwater-repellency of the insulation film surface, it creates problems indevice space and cost points of view.

The present invention has been achieved in light of these problems. Anobject of the present invention is to provide a method of forming aninterlayer insulation film with high mechanical strength and low surfacewater-repellency.

Another object of the present invention is to provide a method offorming an interlayer insulation film with low manufactures' costs andhigh throughput.

To achieve the above-mentioned objects, among others, the presentinvention provides various embodiments including a method of forming aninsulation film on a semiconductor substrate using plasma CVD, whichcomprises the steps of: (a) forming an insulation film on asemiconductor substrate placed in a reaction chamber by introducing asource gas and applying radio-frequency power; and (b) at completion ofthe formation of the film, introducing an oxidizing gas into thereaction chamber and applying radio-frequency power to increasehydrophilicity of a surface of the resulting insulation film. Accordingto this embodiment, hydrophobic Si—H bonds and C—H bonds present on asurface of the insulation film can be converted to hydrophilic Si—OHbonds and C—OH bonds, respectively, thereby increasing hydrophilicity ofthe surface. The insulation film may have a low dielectric constant,high mechanical strength and low surface water-repellency.

In an embodiment, the insulation film can be used for various purposesand may suitably be used as an interlayer insulation film, and themethod may further comprise subjecting the surface of the insulationfilm to chemical mechanical polishing (CMP). With this film, in the CMPprocess of the Damascene interconnect technology, polishing can beperformed evenly, and reliability of the interlayer insulation film canbe improved.

In the above, the present invention further includes, but are notlimited to, the following embodiments: The oxidizing gas may beintroduced with an additive gas. The source gas may be introduced withan additive gas or inert gas such as Ar, He, Ne, and N₂. No or littleoxidizing gas may be used in step (a) so that step (a) forms as theinsulation film a siloxan polymer or oligomer, but not a silicon oxidefilm. Step (b) may be initiated immediately after step (a). Step (b) maybe initiated immediately prior to the completion of step (a). The methodmay further comprise evacuating the reaction chamber after step (a)before step (b). Step (b) may be conducted for at least one secondincluding 2, 3, 5, 10, 20, 30, 40, 50, 60, 100, and 200 seconds, and arange including any of the forgoing (preferably approximately 3-60seconds, further preferably approximately 3-30 seconds). A ratio of theradio-frequency power in step (b) to that in step (a) may be at least1/20 including 1/15, 1/10, 1/5, 1/1, and 2/1, and a range including anyof the forgoing (preferably about 1/10 to about 1/1). High power ispreferable. In step (b), the radio-frequency power may be at least 150mW/cm², preferably at least 250 mW/cm² or any power corresponding to theabove ratio provided that the radio-frequency power in step (a) is 2.5W/cm². Step (b) may continue until a contact angle to water of thesurface of the insulation film becomes 50° or lower, including 40°, 30°,20°, 10°, and 5°, and a range including any of the forgoing. In step(b), the oxidizing gas may be used at a concentration of at least 0.1%,including 0.5%, 1%, 5%, 10%, 20%, 50%, 80%, and 100%, and a rangeincluding any of the forgoing (preferably approximately 0.3%-100%).

In embodiments, any suitable source gas can be used which give the abovecharacteristics, such as those disclosed in U.S. patent application Ser.No. 10/317,239 filed Dec. 11, 2002, which is herein incorporated byreference in its entirety.

In embodiments, the insulation film having low water repellency may havea dielectric constant of 3.5 or lower, preferably 3.1 or lower; and ahardness of 0.5 GPa or higher, preferably 1.0 GPa or higher.

In embodiments of the present invention, an interlayer insulation filmwith low manufactures' cost and high throughput can be formed. Suchembodiments include, but are not limited to, the above-describedembodiments and the embodiments described later.

For purposes of summarizing the invention and the advantages achievedover the prior art, certain objects and advantages of the invention havebeen described above. Of course, it is to be understood that notnecessarily all such objects or advantages may be achieved in accordancewith any particular embodiment of the invention. Thus, for example,those skilled in the art will recognize that the invention may beembodied or carried out in a manner that achieves or optimizes oneadvantage or group of advantages as taught herein without necessarilyachieving other objects or advantages as may be taught or suggestedherein.

Further aspects, features and advantages of this invention will becomeapparent from the detailed description of the preferred embodimentswhich follow.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features of this invention will now be described withreference to the drawings of preferred embodiments which are intended toillustrate and not to limit the invention.

FIG. 1 is a schematic view of plasma CVD equipment usable for methods offorming an interlayer insulation film according to the presentinvention.

FIG. 2 is a diagram showing processing sequence patterns usable formethods of forming an interlayer insulation film according to thepresent invention.

Explanations of symbols used in the figures are as follows: 1: PlasmaCVD equipment; 2: heater; 3: Susceptor; 4: Semiconductor wafer; 5:Source gas inlet port; 6: Reaction chamber; 7: Primary radio-frequencypower source; 8: Secondary radio-frequency power source; 9: Showerhead;10: Exhaust port; 11: Grounding.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

As explained above, in the present invention, various embodiments can beperformed including the following specific examples:

A method of forming an interlayer insulation film on a semiconductorsubstrate using plasma CVD, comprises the steps of: (i) introducing asource gas into a reaction chamber; (ii) applying radio-frequency powerafter the source gas is brought in; (iii) introducing an oxidizing gaswith or without an additive gas into the reaction chamber aftersupplying the source gas and applying the radio-frequency power; and(iv) reinitiating radio-frequency power.

A method of forming an interlayer insulation film on a semiconductorsubstrate using plasma CVD, comprises the steps of: (i) introducing asource gas into a reaction chamber; (ii) applying radio-frequency powerafter the source gas is brought in; and (iii) introducing an oxidizinggas with or without an additive gas into the reaction chambersimultaneously with completion of supplying the source gas.

A method of forming an interlayer insulation film on a semiconductorsubstrate using plasma CVD, comprises the steps of: (i) introducing asource gas into a reaction chamber; (ii) applying radio-frequency powerafter the source gas is brought in; (iii) progressively decreasingsupply of the source gas; and (iv) introducing an oxidizing gas with orwithout an additive gas into the reaction chamber by progressivelyincreasing a feed rate of the oxidizing gas with or without the additivegas as a feed rate of the source gas decreases.

A method of forming an interlayer insulation film on a semiconductorsubstrate using plasma CVD, comprises the steps of: (i) introducing asource gas into a reaction chamber; (ii) applying radio-frequency powerafter the source gas is brought in; and (iii) introducing an oxidizinggas with or without an additive gas into the reaction chamberimmediately before completion of supplying the source gas and applyingthe radio-frequency power.

In the above, the source gas may comprise dimethyl dimethoxysilane(DM-DMOS), or the source gas may further comprises 1,2-propanediol.

Further, the oxidizing gas may comprise at least one selected from thegroup consisting of oxygen, dinitrogenoxide, ozone, hydrogen peroxide,carbon dioxide, and alcohol.

In embodiments, the oxidizing gas may have a concentration of 0.3% to100%. The introduction of the oxidizing gas may continue for threeseconds to 60 seconds. The additive gas may be He, Ar or N₂. The alcoholmay be CH₃OH, C₂H₅OH, or CH₃CH(OH)CH₂.

The present invention is described in detail by referring to figures.The present invention should not be limited thereto. FIG. 1 is aschematic view of plasma CVD equipment usable for methods of forming aninterlayer insulation film having a low dielectric constant, highmechanical strength and low water-repellency according to the presentinvention. The plasma CVD equipment 1 includes a reaction chamber 6.Inside the reaction chamber 6, a susceptor 3 for placing a semiconductorwafer 4 thereon is provided. The susceptor 3 is coupled with a heater 2.The heater 2 keeps the semiconductor wafer 4 at a given temperature(e.g., 350 to 450° C.). The susceptor 3 serves also as one electrode forplasma discharge and is grounded 11 through the reaction chamber 6. Onthe ceiling inside the reaction chamber 6, a showerhead 9 is provided inparallel to and opposed to the susceptor 3. The showerhead 9 has manyfine pores on its bottom surface, from which a jet of source gasdescribed below is emitted to the semiconductor wafer 4. In the centerof the showerhead 9, a source gas inlet port 5 is provided, and thesource gas is brought in through a gas line (not shown) to theshowerhead 9. The gas inlet port 5 is electrically insulated from thereaction chamber 6. The showerhead 9 serves also as the other electrodefor plasma discharge and is connected to an external primaryradio-frequency power source 7 and the external secondaryradio-frequency power source 8 through the source gas inlet port 5. Withthis setup, a plasma reaction field is generated in the proximity of thesemiconductor wafer 4. On the bottom surface of the reaction chamber 6,an exhaust port 10 is provided and is linked to an external vacuum pump(not shown).

In an embodiment, the above-mentioned source gas may comprise a mainsource gas, a sub-source gas and an additive gas. In the presentinvention, further, an oxidizing gas is involved for purposes of surfacetreatment of an insulation film. The main source gas may be siliconhydrocarbon containing multiple alkoxies, preferably DM-DMOS(dimethy-dimethoxysilane), etc. The sub-source gas may be CO₂, alcoholsuch as 1, 2 propanediol, hydrocarbon containing one or more unsaturatedbond, or N₂O, and O₂ or N₂O if controlling a Si/O ratio is required. Theadditive gas may be Ar and/or He. The oxidizing gas may be oxygen,dinitrogenoxide, ozone, hydrogen peroxide, CO₂, or alcohol (CH₃OH,C₂H₅OH, CH₃CH(OH)CH₃, etc.). As a gas diluting the oxidizing gas, N₂,He, Ne, or Ar can be added.

A frequency of the above-mentioned primary radio-frequency power source7 is preferably 27.12 MHz, but it can be other than this if it is 2 MHzor higher (high frequencies). A frequency of the secondaryradio-frequency power source 8 is preferably 400 kHz, but it can beother than this if it is 2 MHz or lower (low frequencies). Selectively,one of two different radio-frequency power sources can be used.

The method of forming an interlayer insulation film having highmechanical strength and low water-repellency according to the presentinvention will be described. FIG. 2 is a diagram showing processingsequence patterns of depositing an interlayer insulation film. In thefigure, the time periods indicated are not accurately scaled and do notrepresent the actual lengths of time periods.

FIG. 2(a) shows a sequence pattern of introducing an oxidizing gas andan additive gas for the oxidizing gas after the supply of a source gasand an additive gas for deposition is stopped. At time t₀ after thesource gas and the additive gas for deposition are brought in, at leastone type of radio-frequency power is applied. At time t₁, the supply ofthe source gas and the additive gas for deposition and the applicationof the radio-frequency power are stopped. At time t₂, an oxidizing gasand an additive gas for the oxidizing gas are brought in. At this time,the concentration of the oxidizing gas is preferably 0.3% or higher. Attime t₃, radio-frequency power is applied again. The power of theradio-frequency power source at this time is preferably {fraction(1/10)} or higher of the power applied during deposition. Finally, attime t₄, the application of the radio-frequency power and the supply ofthe oxidizing gas and the additive gas for the oxidizing gas arestopped. Processing time (t₄−t₃) of the oxidizing gas is preferably inthe range of three seconds to 60 seconds.

In the above, in embodiments, (t₁−t₀) may be approximately 50-200seconds, (t₂−t₁) may be approximately 3-15 seconds (or 5-10 seconds),(t₃−t₂) may be approximately 3-15 seconds (or 5-10 seconds), and (t₄−t₃)may be approximately 3-60 seconds (or 5-40 seconds).

FIG. 2(b) shows a sequence pattern of introducing an oxidizing gas andan additive gas for the oxidizing gas simultaneously with completion ofsupply of a source gas and an additive gas for deposition. At time toafter the source gas and the additive gas for deposition are brought in,at least one type of radio-frequency power is applied. At time t₁,simultaneously with the completion of supplying the source gas and theadditive gas for deposition, an oxidizing gas and an additive gas forthe oxidizing gas are brought in. At this time, the concentration of theoxidizing gas is preferably 0.3% or higher. The power of theradio-frequency power source is preferably {fraction (1/10)} or higherof the power applied during deposition. Finally, at time t₄, theapplication of the radio-frequency power and the supply of the oxidizinggas and the additive gas for the oxidizing gas are stopped. Processingtime (t₄−t₁) of the oxidizing gas is preferably in the range of threeseconds to 60 seconds.

In the above, in embodiments, (t₁−t₀) may be approximately 50-200seconds, and (t₅−t₁) may be approximately 3-60 seconds (or 5-40seconds).

FIG. 2(c) shows another sequence pattern of introducing an oxidizing gasand an additive gas for the oxidizing gas simultaneously with completionof supplying a source gas and an additive gas for deposition. At time toafter the source gas and the additive gas for deposition are brought in,at least one type of radio-frequency power is applied. At time t₁,simultaneously with the completion of supplying the source gas, anoxidizing gas and an additive gas for the oxidizing gas are brought in.At this time, the concentration of the oxidizing gas is preferably 0.3%or higher. The power of the radio-frequency power source is preferably{fraction (1/10)} or higher of the power applied during deposition.Finally, at time t₅, the supply of the additive gas for deposition, theapplication of the radio-frequency power, and the supply of theoxidizing gas and the additive gas for the oxidizing gas are stopped.Processing time (t₅−t₁) of the oxidizing gas is preferably in the rangeof three seconds to 60 seconds.

In the above, in embodiments, (t₁−t₀) may be approximately 50-200seconds, and (t₅−t₁) maybe approximately 3-60 seconds (or 5-40 seconds).

FIG. 2(d) shows a sequence pattern of progressively decreasing supply ofa source gas and an additive gas for deposition and increasing a feedamount of an oxidizing gas and an additive gas for the oxidizing gas asthe supply of the source gas and the additive gas for deposition isdecreased. At time to after the source gas and the additive gas fordeposition are brought in, at least one type of radio-frequency power isapplied. At time t₁, simultaneously with the completion of progressivelydecreasing supply of the source gas and the additive gas for depositionis started, progressively increasing supply of the oxidizing gas and theadditive gas for the oxidizing gas is started. At this time, theconcentration of the oxidizing gas is preferably 0.3% or higher. At atime t₆, simultaneously when progressively decreasing supply of thesource gas and the additive gas for deposition is stopped, progressivelyincreasing a feeding amount of the oxidizing gas and the additive gasfor the oxidizing gas is stopped. Time required (t₆−t₁) for gasswitching is preferably approximately five seconds. During this time,the power of radio-frequency power source is switched to preferably{fraction (1/10)} or higher of the power applied during deposition.Finally, at time t₇, the application of the radio-frequency power andthe supply of the oxidizing gas and the additive gas for the oxidizinggas are stopped. Processing time (t_(7−t) ₆) of the oxidizing gas ispreferably in the range of three seconds to 60 seconds.

In the above, in embodiments, (t₁−t₀) may be approximately 50-200seconds, (t_(6−t) ₁) may be approximately 3-15 seconds (or 5-10seconds), and (t₇−t₆) may be approximately 3-60 seconds (or 5-40seconds).

FIG. 2(e) shows a sequence pattern of introducing an oxidizing gas andan additive gas for the oxidizing gas immediately before the completionof supplying a source gas and an additive gas for deposition. At timet_(o) after the source gas and the additive gas for deposition arebrought in, at least one type of radio-frequency power is applied. Attime t₈, an oxidizing gas and an additive gas for the oxidizing gas arebrought in. At this time, the concentration of the oxidizing gas ispreferably 0.3% or higher. The power of radio-frequency power source ispreferably {fraction (1/10)} or higher of the power applied duringdeposition. Finally, at time t₉, the supply of the source gas and theadditive gas for deposition, the application of the radio-frequencypower and the supply of the oxidizing gas and the additive gas for theoxidizing gas are stopped. Processing time (t₉−t₈) of the oxidizing gasis preferably in the range of three seconds to 60 seconds.

In the above, in embodiments, (t₈−t₀) may be approximately 50-200seconds, and (t₉−t₈) may be approximately 3-60 seconds (or 5-40seconds).

Embodiment

An experiment carried out for evaluating water-repellency of aninsulation film formed according to the methods of forming an interlayerinsulation film according to embodiments of the present invention isdescribed below. Using the plasma CVD equipment shown in FIG. 1, theexperiment was carried out. In the experiment, after a SixCyOz film of 1μm was deposited on a Ø300 mm silicon wafer under deposition conditionsdescribed below, a contact angle against water of the insulation filmobtained by administering processes according to respective sequencepatterns shown in FIG. 2 was determined. A contact angle to water hereis measured as an angle formed by a silicon wafer and a water droplet(0.01-0.1 cc) at room temperature when the water droplet is dropped onthe silicon wafer. The smaller the angle is, the lower thewater-repellency of an insulation film becomes. In the experimentdescribed below, a contact angle of no more than 10° to the waterdroplet was set as an acceptable limit of the water-repellency.

For deposition, the following two conditions were used:

Deposition Condition 1:

DM-DMOS as a main source gas and He as an additive gas were used. Theprimary excitation radio-frequency power was of 27.12 MHz with output at2.5 W/cm², the secondary excitation radio-frequency power was of 400 kHzwith output at 0 W/cm², and these were not overlaid. A depositionpressure at this time was maintained at 400 Pa. A contact angle of afilm obtained is shown as Contact Angle 1.

Deposition Condition 2:

DM-DMOS as a main source gas, 1,2-propanediol as a sub-source gas, andHe as an additive gas were used. The primary excitation radio-frequencypower was of 27.12 MHz with output at 2.5 W/cm², the secondaryexcitation radio-frequency power was of 400 kHz with output at 0.1W/cm², and these were overlaid. A deposition pressure at this time wasmaintained at 400 Pa. A contact angle of a film obtained is shown asContact Angle 2.

Experiment 1

Experimental Conditions:

-   Oxidizing gas: O₂-   Flow of oxidizing gas: 10 to 100 sccm-   Additive gas for oxidizing gas: N₂, He, Ar-   Concentration of oxidizing gas: 0.3% to 100%-   Pressure at oxidizing gas processing: 100 to 800 Pa-   Radio-frequency power during oxidizing gas processing is {fraction    (1/10)} of the power applied at deposition-   Oxidizing gas processing time: 1 to 30 seconds-   Oxidizing gas processing sequence: FIG. 2(a) to (e)-   Time required for gas switching and radio-frequency power switching    in the Sequence-   Pattern shown in FIG. 2(d) (t₆−t₁): 5 seconds    With the above-mentioned conditions, conditions under which a    contact angle of an insulation film to water becomes within 10° were    determined.

TABLE 1 FR C P PT CA 1 CA 2 (sccm) AG (%) (Pa) PS (sec.) (°) (°) NT 6065 1-1  10 N₂ 0.3 400 (a) 1 25 35 1-2  10 N₂ 0.3 400 (a) 3 <10 <10 1-3 10 N₂ 0.3 400 (a) 5 <10 <10 1-4  10 N₂ 0.3 400 (a) 15 <10 <10 1-5  10 N₂0.3 400 (a) 30 <10 <10 1-6  10 N₂ 0.3 100 (a) 3 <10 <10 1-7  10 N₂ 0.3800 (a) 3 <10 <10 1-8  100 — 100 400 (a) 3 <10 <10 1-9  10 He 0.3 400(a) 3 <10 <10 1-10 10 Ar 0.3 400 (a) 3 <10 <10 1-11 10 N₂ 0.3 400 (b) 3<10 <10 1-12 10 N₂ 0.3 400 (c) 3 <10 <10 1-13 10 N₂ 0.3 400 (d) 3 <10<10 1-14 10 N₂ 0.3 400 (e) 3 <10 <10 NT: No Treatment; FR: Flow Rate;AG: Additive Gas; C: Concentration; P: Pressure; PS: ProcessingSequence; PT: Processing Time; CA 1: Contact Angle 1; CA 2: ContactAngle 2.

From the experimental results shown in Table 1, the conditions where anO₂ flow rate was 10 to 100 sccm, an O₂ concentration was 0.3 to 100% (Noadditive gas), a pressure was 100 to 800 Pa, radio-frequency power was{fraction (1/10)} of that applied at deposition, and a processing timeperiod was 3 to 30 seconds, are preferable. It is seen that under theseconditions, the water-repellency of the insulation film is lowered downto the acceptable limit in all sequence patterns.

Experiment 2

Experimental Conditions:

-   Oxidizing gas: Dinitrogenoxide-   Flow of oxidizing gas: 10 to 100 sccm-   Additive gas for oxidizing gas: N₂, He, Ar-   Concentration of oxidizing gas: 0.3% to 100%-   Pressure at oxidizing gas processing: 400 Pa-   Radio-frequency power during oxidizing gas processing is {fraction    (1/10)} of the power applied at deposition-   Oxidizing gas processing time: 3 to 30 seconds-   Oxidizing gas processing sequence: FIG. 2(a) to (e)-   Time required for gas switching and radio-frequency power switching    in the Sequence Pattern shown in FIG. 2(d) (t₆−t₁): 5 seconds    With the above-mentioned conditions, conditions under which a    contact angle of an insulation film to water becomes within 10° were    determined.

TABLE 2 FR C P PT CA 1 CA2 (sccm) AG (%) (Pa) PS (Sec.) (°) (°) NT 60 652-1 10 N₂ 0.3 400 (a) 3 <10 <10 2-2 100 — 100 400 (a) 15 <10 <10 2-3 10He 0.3 400 (a) 3 <10 <10 2-4 10 Ar 0.3 400 (a) 3 <10 <10 2-5 10 N₂ 0.3400 (b) 3 <10 <10 2-6 10 N₂ 0.3 400 (c) 3 <10 <10 2-7 10 N₂ 0.3 400 (d)30 <10 <10 2-8 10 N₂ 0.3 400 (e) 3 <10 <10

From the experimental results shown in Table 2, the conditions where ana dinitrogenoxide flow rate was 10 to 100 sccm, a dinitrogenoxideconcentration was 0.3 to 100% (No additive gas), a pressure was 400 Pa,radio-frequency power was {fraction (1/10)} of that applied atdeposition and processing time of 3 to 30 seconds, are preferable. It isseen that under these conditions, the water-repellency of the insulationfilm is lowered down to the acceptable limit in all sequence patterns.

Experiment 3

Experimental Conditions:

-   Oxidizing gas: Ozone-   Flow of oxidizing gas: 10 sccm-   Additive gas for oxidizing gas: N₂-   Concentration of oxidizing gas: 0.3%-   Pressure at oxidizing gas processing: 400 Pa-   Radio-frequency power during oxidizing gas processing is {fraction    (1/10)} of the power applied at deposition-   Oxidizing gas processing time: 3 to 30 seconds.-   Oxidizing gas processing sequence: FIG. 2(a) to (e)-   Time required for gas switching and radio-frequency power switching    in the Sequence Pattern shown in FIG. 2(d) (t₆−t₀): 5 seconds    With the above-mentioned conditions, conditions under which a    contact angle of an insulation film to water becomes within 10° were    determined.

TABLE 3 FR C P PT CA 1 CA 2 (sccm) AG (%) (Pa) PS (Sec.) (°) (°) NT 6065 3-1 10 N₂ 0.3 400 (a) 15 <10 <10 3-2 10 N₂ 0.3 400 (b) 3 <10 <10 3-310 N₂ 0.3 400 (c) 3 <10 <10 3-4 10 N₂ 0.3 400 (d) 3 <10 <10 3-5 10 N₂0.3 400 (e) 30 <10 <10

From the experimental results shown in Table 3, the conditions where anozone flow rate was 10 sccm, an ozone concentration was 0.3% or higher,a pressure was 400 Pa, radio-frequency power was {fraction (1/10)} ofthat applied at deposition and a processing time period was 3 to 30seconds, are preferable. It is seen that under these conditions, thewater-repellency of the insulation film is lowered down to theacceptable limit in all sequence patterns.

Experiment 4

Experimental Conditions:

-   Oxidizing gas: Hydrogen peroxide-   Flow of oxidizing gas: 10 sccm-   Additive gas for oxidizing gas: N₂-   Concentration of oxidizing gas: 0.3%-   Pressure at oxidizing gas processing: 400 Pa-   Radio-frequency power during oxidizing gas processing is {fraction    (1/10)} of the power applied at deposition-   Oxidizing gas processing time: 3 to 30 seconds-   Oxidizing gas processing sequence: FIG. 2(a) to (e)-   Time required for gas-switching and radio-frequency power switching    in the Sequence Pattern shown in FIG. 2(d) (t₆−t₁): 5 seconds    With the above-mentioned conditions, conditions under which a    contact angle of an insulation film to water becomes within 10° were    determined.

TABLE 4 FR C P PT CA 1 CA 2 (sccm) AG (%) (Pa) PS (Sec.) (°) (°) NT 6065 4-1 10 N₂ 0.3 400 (a) 3 <10 <10 4-2 10 N₂ 0.3 400 (b) 5 <10 <10 4-310 N₂ 0.3 400 (c) 3 <10 <10 4-4 10 N₂ 0.3 400 (d) 30 <10 <10 4-5 10 N₂0.3 400 (e) 15 <10 <10

From the experimental results shown in Table 4, the conditions where ahydrogen peroxide flow rate was 10 sccm, a hydrogen peroxideconcentration was 0.3% or higher, a pressure was 400 Pa, radio-frequencypower was {fraction (1/10)} of that applied at deposition and aprocessing time period was 3 to 30 seconds, are preferable. It is seenthat under these conditions, the water-repellency of the insulation filmis lowered down to the acceptable limit in all sequence patterns.

Experiment 5

Experimental Conditions:

-   Oxidizing gas: CO₂-   Flow of oxidizing gas: 10 sccm-   Additive gas for oxidizing gas: N₂-   Concentration of oxidizing gas: 0.3%-   Pressure at oxidizing gas processing: 400 Pa-   Radio-frequency power during oxidizing gas processing is {fraction    (1/10)} of the power applied at deposition-   Oxidizing gas processing time: 3 to 30 seconds-   Oxidizing gas processing sequence: FIG. 2(a) to (e)-   Time required for gas switching and radio-frequency power switching    in the Sequence Pattern shown in FIG. 2(d) (t₆−t₁): 5 seconds    With the above-mentioned conditions, conditions under which a    contact angle of an insulation film to water becomes within 10° were    determined.

TABLE 5 FR C P PT CA 1 CA 2 (sccm) AG (%) (Pa) PS (Sec.) (°) (°) NT 6065 5-1 10 N₂ 0.3 400 (a) 3 <10 <10 5-2 10 N₂ 0.3 400 (b) 15 <10 <10 5-310 N₂ 0.3 400 (c) 3 <10 <10 5-4 10 N₂ 0.3 400 (d) 3 <10 <10 5-5 10 N₂0.3 400 (e) 30 <10 <10

From the experimental results shown in Table 5, the conditions where aCO₂ flow rate was 10 sccm, a CO₂ concentration was 0.3% or higher, apressure was 400 Pa, radio-frequency power was {fraction (1/10)} of thatapplied at deposition and a processing time period was 3 to 30 seconds,are preferable. It is seen that under these conditions, thewater-repellency of the insulation film is lowered down to theacceptable limit in all sequence patterns.

Experiment 6

Experimental Conditions:

-   Oxidizing gas: CH₃OH-   Flow of oxidizing gas: 10 sccm-   Additive gas for oxidizing gas: N₂-   Concentration of oxidizing gas: 0.3%-   Pressure at oxidizing gas processing: 400 Pa-   Radio-frequency power during oxidizing gas processing is {fraction    (1/10)} of the power applied at deposition-   Oxidizing gas processing time: 3 to 30 seconds-   Oxidizing gas processing sequence: FIG. 2(a) to (e)-   Time required for gas switching and radio-frequency power switching    in the Sequence Pattern shown in FIG. 2(d) (t₆−t₁): 5 seconds    With the above-mentioned conditions, conditions under which a    contact angle of an insulation film to water becomes within 10° were    determined.

TABLE 6 FR C P PT CA 1 CA 2 (sccm) AG (%) (Pa) PS (Sec.) (°) (°) NT 6065 6-1 10 N₂ 0.3 400 (a) 15 <10 <10 6-2 10 N₂ 0.3 400 (b) 3 <10 <10 6-310 N₂ 0.3 400 (c) 3 <10 <10 6-4 10 N₂ 0.3 400 (d) 30 <10 <10 6-5 10 N₂0.3 400 (e) 3 <10 <10

From the experimental results shown in Table 6, the conditions where aCH₃OH flow rate was 10 sccm, a CH₃OH₂ concentration was 0.3% or higher,a pressure was 400 Pa, radio-frequency power was {fraction (1/10)} ofthat applied at deposition and a processing time period was 3 to 30seconds, are preferable. It is seen that under these conditions, thewater-repellency of the insulation film is lowered down to theacceptable limit in all sequence patterns.

Experiment 7

Experimental Conditions:

-   Oxidizing gas: C₂H₅OH-   Flow of oxidizing gas: 10 sccm-   Additive gas for oxidizing gas: N₂-   Concentration of oxidizing gas: 0.3%-   Pressure at oxidizing gas processing: 400 Pa-   Radio-frequency power during oxidizing gas processing is {fraction    (1/10)} of the power applied at deposition-   Oxidizing gas processing time: 3 to 30 seconds-   Oxidizing gas processing sequence: FIG. 2(a) to (e)-   Time required for gas switching and radio-frequency power switching    in the Sequence Pattern shown in FIG. 2(d) (t₆−t₀): 5 seconds    With the above-mentioned conditions, conditions under which a    contact angle of an insulation film to water becomes within 10° were    determined.

TABLE 7 FR C P PT CA 1 CA 2 (sccm) AG (%) (Pa) PS (Sec.) (°) (°) NT 6065 7-1 10 N₂ 0.3 400 (a) 30 <10 <10 7-2 10 N₂ 0.3 400 (b) 3 <10 <10 7-310 N₂ 0.3 400 (c) 15 <10 <10 7-4 10 N₂ 0.3 400 (d) 3 <10 <10 7-5 10 N₂0.3 400 (e) 3 <10 <10

From the experimental results shown in Table 7, the conditions where aC₂H₅OH flow rate was 10 sccm, a C₂H₅OH concentration was 0.3% or higher,a pressure was 400 Pa, radio-frequency power was {fraction (1/10)} ofthat applied at deposition and a processing time period was 3 to 30seconds, are preferable. It is seen that under these conditions, thewater-repellency of the insulation film is lowered down to theacceptable limit in all sequence patterns.

Experiment 8

Experimental Conditions:

-   Oxidizing gas: C₃CH(OH)CH₃-   Flow of oxidizing gas: 10 sccm-   Additive gas for oxidizing gas: N₂-   Concentration of oxidizing gas: 0.3%-   Pressure at oxidizing gas processing: 400 Pa-   Radio-frequency power during oxidizing gas processing is {fraction    (1/10)} of the power applied at deposition-   Oxidizing gas processing time: 3 to 30 seconds-   Oxidizing gas processing sequence: FIG. 2(a) to (e)-   Time required for gas switching and radio-frequency power switching    in the Sequence Pattern shown in FIG. 2(d) (t₆−t₁): 5 seconds    With the above-mentioned conditions, conditions under which a    contact angle of an insulation film to water becomes within 10° were    determined.

TABLE 8 FR C P PT CA 1 CA 2 (sccm) AG (%) (Pa) PS (Sec.) (°) (°) NT 6065 8-1 10 N₂ 0.3 400 (a) 3 <10 <10 8-2 10 N₂ 0.3 400 (b) 3 <10 <10 8-310 N₂ 0.3 400 (c) 15 <10 <10 8-4 10 N₂ 0.3 400 (d) 3 <10 <10 8-5 10 N₂0.3 400 (e) 30 <10 <10

From the experimental results shown in Table 8, the conditions where aC₃CH(OH)CH₃ flow rate was 10 sccm, a C₃CH(OH)CH₃ concentration was 0.3%or higher, a pressure was 400 Pa, radio-frequency power was {fraction(1/10)} of that applied at deposition and a processing time period was 3to 30 seconds, are preferable. It is seen that under these conditions,the water-repellency of the insulation film is lowered down to theacceptable limit in all sequence patterns.

Effects

Using the methods of forming an interlayer insulation film according tothe embodiments, an interlayer insulation film having a low dielectricconstant, high mechanical strength and low surface water-repellency wasformed effectively. With this film, in the CMP process of the Damasceneinterconnect technology, polishing can be performed evenly, andreliability of insulation can be improved.

Additionally, using the methods of forming an interlayer insulation filmaccording to the embodiments, an interlayer insulation film with lowmanufactures' cost and high throughput was formed effectively.

It will be understood by those of skill in the art that numerous andvarious modifications can be made without departing from the spirit ofthe present invention. Therefore, it should be clearly understood thatthe forms of the present invention are illustrative only and are notintended to limit the scope of the present invention.

1. A method of forming an insulation film on a semiconductor substrate using plasma CVD, which comprises the steps of: (a) forming an insulation film on a semiconductor substrate placed in a reaction chamber by introducing a source gas and applying radio-frequency power; and (b) solely at completion of the formation of the film, introducing an oxidizing gas into the reaction chamber and applying radio-frequency power to increase hydrophilicity of a surface of the resulting insulation film.
 2. The method according to claim 1, wherein the oxidizing gas is introduced with an additive gas.
 3. The method according to claim 1, wherein the source gas is introduced with an additive gas.
 4. A method of forming an insulation film on a semiconductor substrate using plasma CVD, which comprises the steps of: (a) forming an insulation film on a semiconductor substrate placed in a reaction chamber by introducing a source gas and applying radio-frequency power; and (b) at completion of the formation of the film, introducing an oxidizing gas into the reaction chamber and applying radio-frequency power to increase hydrophilicity of a surface of the resulting insulation film, wherein no oxidizing gas is used in step (a).
 5. The method according to claim 1, wherein step (b) is initiated immediately after step (a).
 6. A method of forming an insulation film on a semiconductor substrate using plasma CVD, which comprises the steps of: (a) forming an insulation film on a semiconductor substrate placed in a reaction chamber by introducing a source gas and applying radio-frequency power; and (b) at completion of the formation of the film, introducing an oxidizing gas into the reaction chamber and applying radio-frequency power to increase hydrophilicity of a surface of the resulting insulation film, wherein step (b) is initiated immediately prior to the completion of step (a).
 7. A method of forming an insulation film on a semiconductor substrate using plasma CVD, which comprises the steps of: (a) forming an insulation film on a semiconductor substrate placed in a reaction chamber by introducing a source gas and applying radio-frequency power; (b) at completion of the formation of the film, introducing an oxidizing gas into the reaction chamber and applying radio-frequency power to increase hydrophilicity of a surface of the resulting insulation film; and (c) evacuating the reaction chamber after step (a) before step (b).
 8. The method according to claim 1, wherein step (b) is conducted for approximately 3-60 seconds.
 9. The method according to claim 1, wherein step (a) forms a siloxan polymer or oligomer film as the insulation film.
 10. A method of forming an insulation film on a semiconductor substrate using plasma CVD, which comprises the steps of: (a) forming an insulation film on a semiconductor substrate placed in a reaction chamber by introducing a source gas and applying radio-frequency power; and (b) at completion of the formation of the film, introducing an oxidizing gas into the reaction chamber and applying radio-frequency power to increase hydrophilicity of a surface of the resulting insulation film, wherein a ratio of the radio-frequency power in step (b) to that in step (a) is about 1/10 to about 1/1.
 11. The method according to claim 1, wherein in step (b), the radio-frequency power is at least 150 mW/cm².
 12. A method of forming an insulation film on a semiconductor substrate using plasma CVD, which comprises the steps of: (a) forming an insulation film on a semiconductor substrate placed in a reaction chamber by introducing a source gas and applying radio-frequency power; and (b) at completion of the formation of the film, introducing an oxidizing gas into the reaction chamber and applying radio-frequency power to increase hydrophilicity of a surface of the resulting insulation film, wherein step (b) continues until a contact angle to water of the surface of the insulation film becomes 10° or lower.
 13. The method according to claim 1, wherein in step (b), the oxidizing gas is used at a concentration of approximately 0.3%-100%.
 14. A method of forming an insulation film on a semiconductor substrate using plasma CVD, which comprises the steps of: (a) forming an insulation film on a semiconductor substrate placed in a reaction chamber by introducing a source gas and applying radio-frequency power; and (b) at completion of the formation of the film, introducing an oxidizing gas into the reaction chamber and applying radio-frequency power to increase hydrophilicity of a surface of the resulting insulation film, wherein the insulation film is an interlayer insulation film and the method further comprises subjecting the surface of the insulation film to chemical mechanical polishing (CMP).
 15. A method of forming an interlayer insulation film on a semiconductor substrate using plasma CVD, which comprises the steps of: introducing a source gas into a reaction chamber; applying radio-frequency power after the source gas is brought in; introducing an oxidizing gas with or without an additive gas into the reaction chamber solely after supplying the source gas and applying the radio-frequency power; and reinitiating radio-frequency power.
 16. A method of forming an interlayer insulation film on a semiconductor substrate using plasma CVD, which comprises the steps of: introducing a source gas into a reaction chamber; applying radio-frequency power after the source gas is brought in; and introducing an oxidizing gas with or without an additive gas into the reaction chamber solely simultaneously with completion of supplying the source gas.
 17. A method of forming an interlayer insulation film on a semiconductor substrate using plasma CVD, which comprises the steps of: introducing a source gas into a reaction chamber; applying radio-frequency power after the source gas is brought in; progressively decreasing supply of the source gas; and introducing an oxidizing gas with or without an additive gas into the reaction chamber by progressively increasing a feed rate of the oxidizing gas with or without the additive gas as a feed rate of the source gas decreases.
 18. A method of forming an interlayer insulation film on a semiconductor substrate using plasma CVD, which comprises the steps of: introducing a source gas into a reaction chamber; applying radio-frequency power after the source gas is brought in; and introducing an oxidizing gas with or without an additive gas into the reaction chamber solely immediately before completion of supplying the source gas and applying the radio-frequency power.
 19. The method according to any one of claims 15 to 18, wherein said source gas comprises dimethyl dimethoxysilane (DM-DMOS).
 20. The method according to claim 19, wherein said source gas further comprises 1,2-propanediol.
 21. The method according to any one of claims 15 to 18, wherein said oxidizing gas comprises at least one selected from the group consisting of oxygen, dinitrogenoxide, ozone, hydrogen peroxide, carbon dioxide, and alcohol.
 22. The method according to any one of claims 15 to 18, wherein said oxidizing gas has a concentration of 0.3% to 100%.
 23. The method according to any one of claims 15 to 18, wherein the introduction of the oxidizing gas continues for three seconds to 60 seconds.
 24. The method according to any one of claims 15 to 18, wherein said additive gas is He, Ar or N₂.
 25. The method according to claim 21, wherein said alcohol is CH₃OH, C₂H₅OH or CH₃CH(OH)CH₂. 